title: Human mesenchymal stem cell-replicative senescence and oxidative stress are closely linked to aneuploidy.
abstract: In most clinical trials, human mesenchymal stem cells (hMSCs) are expanded in vitro before implantation. The genetic stability of human stem cells is critical for their clinical use. However, the relationship between stem-cell expansion and genetic stability is poorly understood. Here, we demonstrate that within the normal expansion period, hMSC cultures show a high percentage of aneuploid cells that progressively increases until senescence. Despite this accumulation, we show that in a heterogeneous culture the senescence-prone hMSC subpopulation has a lower proliferation potential and a higher incidence of aneuploidy than the non-senescent subpopulation. We further show that senescence is linked to a novel transcriptional signature that includes a set of genes implicated in ploidy control. Overexpression of the telomerase catalytic subunit (human telomerase reverse transcriptase, hTERT) inhibited senescence, markedly reducing the levels of aneuploidy and preventing the dysregulation of ploidy-controlling genes. hMSC-replicative senescence was accompanied by an increase in oxygen consumption rate (OCR) and oxidative stress, but in long-term cultures that overexpress hTERT, these parameters were maintained at basal levels, comparable to unmodified hMSCs at initial passages. We therefore propose that hTERT contributes to genetic stability through its classical telomere maintenance function and also by reducing the levels of oxidative stress, possibly, by controlling mitochondrial physiology. Finally, we propose that aneuploidy is a relevant factor in the induction of senescence and should be assessed in hMSCs before their clinical use.
authors.affiliation: Department of Cardiovascular Development and Repair, Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Melchor Fernández Almagro 3, Madrid, Spain.
authors.forename: J C
authors.initials: JC
authors.lastname: Estrada
authors.forename: Y
authors.initials: Y
authors.lastname: Torres
authors.forename: A
authors.initials: A
authors.lastname: Benguría
authors.forename: A
authors.initials: A
authors.lastname: Dopazo
authors.forename: E
authors.initials: E
authors.lastname: Roche
authors.forename: L
authors.initials: L
authors.lastname: Carrera-Quintanar
authors.forename: R A
authors.initials: RA
authors.lastname: Pérez
authors.forename: J A
authors.initials: JA
authors.lastname: Enríquez
authors.forename: R
authors.initials: R
authors.lastname: Torres
authors.forename: J C
authors.initials: JC
authors.lastname: Ramírez
authors.forename: E
authors.initials: E
authors.lastname: Samper
authors.forename: A
authors.initials: A
authors.lastname: Bernad
mesh_terms: D000782:Aneuploidy; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D016922:Cellular Senescence; D054377:Chemokine CXCL12 / Q000235:genetics / Q000378:metabolism; D018260:Gelsolin / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation; D042822:Genomic Instability; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D018384:Oxidative Stress; D010101:Oxygen Consumption; D017382:Reactive Oxygen Species / Q000378:metabolism; D019098:Telomerase / Q000378:metabolism; D059505:Telomere Homeostasis
chemical_list: C515255:CXCL12 protein, human; D018797:Cell Cycle Proteins; D054377:Chemokine CXCL12; D018260:Gelsolin; D017382:Reactive Oxygen Species; C065395:scinderin; D019098:Telomerase